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Kegelite: infrared spectroscopy and a structural hypothesis

Published online by Cambridge University Press:  05 July 2018

R. S. W. Braithwaite*
Affiliation:
Chemistry Department, University of Manchester Institute of Science and Technology, Manchester M60 1QD, England

Abstract

The infrared spectrum of kegelite has been measured and is discussed. The infrared spectra of 1 : 1 molar mixtures of leadhillite with pyrophyllite or with muscovite resemble the spectrum of kegelite, the chemical formula of which is a 1 : 1 stoichiometric sum of those of pyrophyllite and of the leadhillite polymorphs. Kegelite is not a physical mixture of these species, but its structure may be an interlayering of phyllosilicate and leadhillite-like structures within the unit cell. The unit cell parameters of pyrophyllite-1Tc and the leadhillite polymorphs are compatible with each other and can be combined to give a cell with parameters close to those of the kegelite cell. A structural model for kegelite on these bases is suggested, which is also consistent with its thermal analysis. The formula of kegelite can be written as Pb8(SO4)2(CO3)4(OH)4(AlOH)4(Si4O10)2.

Type
Research Article
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1991

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